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Evolved from autocross to road racing and it's time to get some new tires. I have another set of wheels I would swap at the track so r compounds are a possibility.
I honestly don't plan on keeping the 8 as a track car so don't really wanna put money into anything else. What would be a good setup? Obviously I would get an alignment done too if necessary.
It depends more on your skill level than the car. The racier the tire the less forgiving it is, and the faster it wears out. That said, I wouldn't go below Hankook RS3 or BFG Rivals. My personal preference are RS3's, but Rivals seem to be a bit faster in professional tests.
The second biggest mistake, related to the biggest mistake, is more tire than suspension. If you have factory spring rates, or even a little heavier, anything beyond the RS3 or Rival will get destroyed by the body roll they induce. There is just too much grip. Massive anti-roll bars only help a little and can make the car a PITA on the street. I am in the Rival camp, but the RS3 is grand as well. Keep front pressures high, like 36 cold, or the roll in the front will just cut through the shoulder of the tire. I trashed a set before I got pressures up this high.
The second biggest mistake, related to the biggest mistake, is more tire than suspension. If you have factory spring rates, or even a little heavier, anything beyond the RS3 or Rival will get destroyed by the body roll they induce. There is just too much grip. Massive anti-roll bars only help a little and can make the car a PITA on the street. I am in the Rival camp, but the RS3 is grand as well. Keep front pressures high, like 36 cold, or the roll in the front will just cut through the shoulder of the tire. I trashed a set before I got pressures up this high.
So I'm not crazy! I ran about that front pressure and it worked great, but everyone gave me the crooked eye when I mentioned it. To be fair they were also atarting to scallop, so it might be a trade-off between heat and shoulder roll. I went to lower pressure on my current Rivals, but they feel meh. I'll try going back up. The rival seems to have a loy more shoulder anyway.
I am about to do some time attacks for fun. the first couple events are soon and not for any points so I am just going to run the tires that are on the stock wheels. My class allows my car to run up to a 245/40/18 tire. I am running it on a 18x9.5"
which tire to choose.
R-S3, RE-11A, RE-71R
the cost difference is $159 (R-S3), $166 (RE-11A), $190 (RE-71R)
I don't have to win, just wondering what everyone would go with. I have the RE-11 on my FD and I like them a lot, my buddies say RE-71R all day but they wear out quicker, R-S3 are on sale....same with the RE-11A.
The R-S3 is the price leader right now because Hankook is rolling out the R-S4. I've noticed that the R-S3 and RE-11A are both pretty hard-wearing and don't mind heat as much as the RE-71R. That said, neither has the ultimate grip of the RE-71R.
For my money, I'd go with the R-S3 (and I'm planning to if I can get some cash together before they run out of my size).
The RS3 is a great tire, except when the track is cold. It isn't a winter track day tire. Rivals are much better in the cold. It is also not so good in the rain. It is, however, a very good warm, dry weather tire. It has a lot of grip in its preferred conditions and is long-lived.
The RE-11 is a great all-around performer. Good grip wet and dry, cold and warm. Lasts a long time. (I think I got 12 track days out of a set). I have not used the A variant.
The RE-71R has monster grip, but I think of it more as an autoX tire. It comes on fast, rewards early laps, then falls off is it overheats midway through a session. It also wears quickly and strangely. It has a feeling of "squirm" in hard cornering--even when not over-driven. I can't really describe it better than that. I went through 2 sets in 1 year, and that required flipping them on their rims and living with that resultant weirdness.
Another option is Star Specs. I find them to be between RE-11s and Rivals in all-around performance. A friend of mine runs 10 to 12 track days per year, and he just finished his Star Specs off at the end of his 2nd year on them.
If it were me, and you want to stay off R comps, get the most grip in the most conditions, and enjoy good treadwear, I would go with Rivals.
If you want to put up fast times, go with RE-71Rs, and embrace the idiosyncrasies and fast wear.
One of the reasons I quit doing time trials is, the guy with the biggest rubber budget almost always wins.
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Last edited by Steve Dallas; 01-24-2017 at 08:37 AM.
Reason: Added Star Specs to the list
So I'm not crazy! I ran about that front pressure and it worked great, but everyone gave me the crooked eye when I mentioned it. To be fair they were also atarting to scallop, so it might be a trade-off between heat and shoulder roll. I went to lower pressure on my current Rivals, but they feel meh. I'll try going back up. The rival seems to have a loy more shoulder anyway.
Cannot confirm or deny the first part, : )
But the tire works well at that pressure on a stock suspension. I could run it down with my coil overs, but that was after I managed the body roll. Coil overs are 9K/7K, or 500/350 ish lb/inch, or 4x stiffer than stock.
But the tire works well at that pressure on a stock suspension. I could run it down with my coil overs, but that was after I managed the body roll. Coil overs are 9K/7K, or 500/350 ish lb/inch, or 4x stiffer than stock.
What kind of spring rate are you running?
Stock R3 springs, not sure what rate they are. Can confirm body roll is not managed
Keeping an eye out for a good suspension set up, but not in a hurry to class up. Plus, I have a specific time I want to hit at Mont-Tremblant on factory suspension.
I have similar dilemma on what tires to run on my S2 - stock suspension plus hochiks sway bars. I run 3-4 HPDE events per year in solo advanced groups. I have just used up set of NT-01s on S1 wheels. They were 245/40/18 and as you guys mentioned I think this is to much tire for stock suspension as I wore out outsides of the tires.
so what is the track expert wisdom on these two questions:
1. For the stock S1 wheel which is 8" wide what tire width will have best handling characteristics on the track. For example some of the 245 tires I am looking at have thread with of 9"+ creating inverted trapezoid , while 225 have ~8" thread width giving you more square setup that is also lighter by several pounds as well. So which is better for the track duty again with preference for durability, good handling and more even wear while providing good grip?
2. Second question is about total wheel/tire combo unsprung weight and it's impact on performance. I know RE11 is somewhat gripper tire than MPSS but it is also much heavier.
For example MPSS is only 22lb in 225/40/18 while RE11 is 25lb per tire in the same size. this is all unsprung weight. On S1 wheels, that weigh 22lb, total weight would be 44 for MPSS vs 47lb for RE11 per wheel. Another question is for you guys running 17x9 RPF1s or other lighter wheels - How much difference did the lighter wheel/tire combo made in terms of track handling, steering response, breaking and acceleration?
Again looking for a track only tire that is reasonably fast but more importantly that will not get greasy in the second half of the session with decent thread life and that will also do well in cooler temperatures for the early spring/late fall DE events. Right now I am considering MPSS, RS3 and RE-11...Both bridgestone and michelin have 70 rebate now as well but that is not prevailing factor.
Originally Posted by NotAPreppie
If you decide to go with the R-S3 in 245/40-18, it's currently on closeout at TireRack for $115+shipping.
NT-01s are definitely too much tire for the stock suspension. Wearing the outside of the tires also has very much to do with the amount of negative camber you have in your alignment, and the section width vs. the rim width.
I am about to post something that is controversial among casual readers and many autocrossers and track rats. It took me 3 years to learn this lesson, and it is absolutely true.
The size of the contact patch has more to do with rim width than section width.
I noticed this, when I started studying the setups of the top time trialers in my area. All are running configurations that would be considered slightly "stretched". Among the Miata guys, 225 tires on 9" rims are the norm.
A deep dive into tire manufacturer's data shows why they do this. The realized tread width is the same from the middle to the wide side of the recommended rim width range, but narrows on slimmer rims.
By slightly stretching the tire, you get the widest contact patch possible with a stiffer sidewall to minimize flex and squirm. Stuffing the the widest tire you can onto a given rim width is actually counter-productive, as it encourages edge roll and uneven wear, without increasing the width of the contact patch.
Here are some examples. This bit comes courtesy of 949 Racing via Flyin' Miata:
From my own garage, this is a 255 tire on a 9" rim:
And, from my own living room, this is a 225 tire on a 9" rim:
This fact allows you to run a lighter tire on your rims with less tire wear, without sacrificing contact patch.
As for the weight difference, you are not only saving unsprung weight, but also rotational mass, so there is more than one benefit. In my experience, you can feel a difference of about 5lbs or more.
I have not driven on MPSS tires, so I cannot offer any advice there.
Last edited by Steve Dallas; 02-06-2017 at 06:55 PM.
that first picture with NT-01a is exactly what I am talking about in my question #1, essentially they are saying your thread width should not exceed your rim width and preferably rim should be slightly wider to get the inverse trapezoid shape.
"1. Increased tension on sidewall reduces unwanted deflection and distortion.
a. Quicker steering response
b. Reduce camber loss from sidewall deflection
c. More linear steering response at max slip angle
2. Increased air volume
a. Lower pressures allow tread to conform to road surface better, improving grip.
b. Increased air volume temperature fluctuates less with thread heating/cooling.
3. Contact patch is increased by decreasing psi loading per unit area (lower air pressure and wider rim). Imagine pressing hard inflated basketball onto ground or mostly deflated basketball onto ground.
a. By lowering loading per unit area, total friction potential per unit area is increased.
b. Tire wear pattern is more even
c. Tire wear rate is improved
In general, a Spec Miata with 205/50 NT01's on 15x7's will run around 39psi hot. The same car with 225/45's on 15x9's will run around 30psi hot
and generate about .25g more lateral grip"
Ideally I would like to pick up used set of 17x9 RPF1s (15.9lb) with some nice rubber already on them or just wheels. Anyone?
Any other light weight 17x9 wheels that can be found used cheap?
Also found that Kosei K5R 17x9 with 48mm offset are just under $740 shipped. These are only 1lb heavier than RPF1. Are they any good?
S1 stock wheels are 22lb and S2 are surprisingly even heavier at almost 24lb according to my scale.
Save
Last edited by Nadrealista; 02-06-2017 at 08:23 PM.
When talking about wheels, weight is actually the last thing you should worry about.
1) wheel width, and stretching the tire onto the wheel slightly. general rule of thumb is a .5" to 1" wider than the tread width.
2) Wheel strength. how rigid the wheel is more important than the weight of the wheel.
3) wheel weight given you have good width and rigidity.
I have experimented with my rx7 FD and the car drives so damn well with 11.5" wide wheels. the grip is insane, the car rides smoother (think of going over potholes, not in them) and the wheels I chose are strong (NT03).
A quick synopsis is below:
Regular High Rigidity Enkei GTC-01 18×10 +22: 23.76 lbs.
Specially Lightened Version Enkei GTC-01 18×10 +22: 19.8 lbs.
The weight of the lightened version was reduced by 3.96 lbs. Both used Advan A048 (265/35-18 M-Compound). Testing was performed at Ebisu East Circuit using MCR’s Z33 driven by Kobayashi and under the same specs (ie., tire pressure, # of laps, etc.)
Regular High Rigidity GTC-01
Best Lap: 1 min. 4.646 seconds
Top Speed: 147.16 km/h @ 17.83 seconds
Specially Lightened GTC-01
Best Lap: 1 min. 5.045 seconds
Top Speed: 141.46 km/h @ 17.74 seconds
A very rough and quick recap: The surface temperature of the tires for the less rigid, specially lightened GTC-01 were higher overall with extensive wear on the outer portion while not enough contact/usage on the inner portion. The high rigidity regular version GTC-01 showed even usage throughout the inner and outer parts of the tire. Also, the low rigidity, lightweight version wheels gave/bent when taking aggressive high speed turns even affecting the height of the car which even led to scraping and alignment problems. Furthermore, the lighter version accelerated much quicker, but ultimately did not lead to faster times. In summary, Kobayashi expressed that a balanced wheel with both rigidity and lightweight characteristics is important, but he never imagined that the effects of rigidity played such a large role.
The tire/wheel width relationship recommendations assume you aren't limited by mechanics or rules.
Many competitive RX-8 autocrossers found time fitting 285-width Hoosier A6 tires to 18x8 wheels in Stock/Street class. Was it ideal? No but they were limited by rules to the OEM wheel size at the time but there was no limit on tire size.
great info, this makes me wonder if my NT01s were wearing more on the outside because 245/40 18 has 9" thread width that was fitted over the stock 8" wheel
I was also looking at NT01s in 225/40 size but their load index is only 88 which lower than what mazda specs (91). not sure it would be wise to run lower load index tire on the track?
RE71 in 225/40/18 have 7.6" thread width while MPSS is 7.9", so RE71 is closer to that ideal rim to tire thread width ratio.
Again my focus is on the HPDE tire that can take 25-30 min sessions without overheating/getting greasy. I wonder if RE71 is more of a autocross tire?
Last edited by Nadrealista; 02-08-2017 at 09:00 AM.
great info, this makes me wonder if my NT01s were wearing more on the outside because 245/40 18 has 9" thread width that was fitted over the stock 8" wheel
I was also looking at NT01s in 225/40 size but their load index is only 88 which lower than what mazda specs (91). not sure it would be wise to run lower load index tire on the track?
RE71 in 225/40/18 have 7.6" thread width while MPSS is 7.9", so RE71 is closer to that ideal rim to tire thread width ratio.
Again my focus is on the HPDE tire that can take 25-30 min sessions without overheating/getting greasy. I wonder if RE71 is more of a autocross tire?
heresay is the re-71 is super grippy when colder, when heated up gets slick. so perhaps a different tire would be a better selection for track duty if that is what you are mainly doing.
A lot of people say how precise the steering is on the re-71....my reasoning behind this is the re-71 and re-11 have less tread width and Bridgestone did a better job of guessing what the consumer would use the tire on for a specific width. say a 245 on a 9" wheel, or a 255 on a 9.5" wheel so they made the tread widths not as wide to get better steering and traction with what most consumers would run specific rim widths on. you can see this clearly with the tread width differences between 255/265 tires on some models. they are almost the same.
your 245's probably wore like that because of two things. they are muffin topped and the tire is moving around, and/or they are underinflated. The stretching of the tire makes the tire less sensitive to pressure differences.
I noticed that on my cars, on my FD I run 32F and 30R cold pressure and the tread wear is even and great, on other cars if I run this inflation the outside of the tires wear bad, if I pump them up to 35-40PSI the tread wear is much better.
My experience with RE-71R tires in the Texas summer heat is, they do get greasy about halfway through a session and wear unevenly and quickly once overheated. They are great for any application, in which you need grip to come on fast and last a short time, like time trials or autoX. I do not find them to be a particularly good track day tire. There are better options for the money.
My experience with RE-71R tires in the Texas summer heat is, they do get greasy about halfway through a session and wear unevenly and quickly once overheated. They are great for any application, in which you need grip to come on fast and last a short time, like time trials or autoX. I do not find them to be a particularly good track day tire. There are better options for the money.
Interesting, perhaps RE11 or MPSS are better choices? What do you recommend?
heresay is the re-71 is super grippy when colder, when heated up gets slick. so perhaps a different tire would be a better selection for track duty if that is what you are mainly doing.
A lot of people say how precise the steering is on the re-71....my reasoning behind this is the re-71 and re-11 have less tread width and Bridgestone did a better job of guessing what the consumer would use the tire on for a specific width. say a 245 on a 9" wheel, or a 255 on a 9.5" wheel so they made the tread widths not as wide to get better steering and traction with what most consumers would run specific rim widths on. you can see this clearly with the tread width differences between 255/265 tires on some models. they are almost the same.
your 245's probably wore like that because of two things. they are muffin topped and the tire is moving around, and/or they are underinflated. The stretching of the tire makes the tire less sensitive to pressure differences.
I noticed that on my cars, on my FD I run 32F and 30R cold pressure and the tread wear is even and great, on other cars if I run this inflation the outside of the tires wear bad, if I pump them up to 35-40PSI the tread wear is much better.
I tried to keep NT-01 hot pressures at 38psi f/r. maybe that was not sufficient? It didn't look like I was rolling the past sidewall but wear was mostly on the outer edge.
Interesting, perhaps RE11 or MPSS are better choices? What do you recommend?
I wonder if I could get by on 225/40 18 NT-01s?
RE11s are good. So are Star Specs, Rivals, R-S3s, etc. A lot of people I know just buy one of those based on price and are happy with that approach. I have not driven on MPSS tires, so I can't comment on them, but I see a lot of them on Vettes, Porsches, etc. at the track.
NT01s should be fine at the right width for your rims as well. People seem to love to hate them for some reason, but they are great tires for their intended purpose.
01-20-2017, 12:31 PM
